It is desirable to increase the dietary intake of the beneficial omega-3 polyunsaturated fatty acids (omega-3 PUFA), and omega-3 long chain polyunsaturated fatty acids (omega-3 LC PUFA). As used herein, reference to a long chain polyunsaturated fatty acid or LC PUFA, refers to a polyunsaturated fatty acid having 18 or more carbons. Omega-3 PUFAs are recognized as important dietary compounds for preventing arteriosclerosis and coronary heart disease, for alleviating inflammatory conditions, cognitive impairment and dementia related diseases and for retarding the growth of tumor cells. One important class of omega-3 PUFAs is omega-3 LC PUFAs.
Fatty acids are carboxylic acids and are classified based on the length and saturation characteristics of the carbon chain. Short chain fatty acids have 2 to about 6 carbons and are typically saturated. Medium chain fatty acids have from about 6 to about 16 carbons and may be saturated or unsaturated. Long chain fatty acids have from 18 to 24 or more carbons and may also be saturated or unsaturated. In longer fatty acids there may be one or more points of unsaturation, giving rise to the terms “monounsaturated” and “polyunsaturated”, respectively. Long chain PUFAs (LC PUFAs) are of particular interest in the present invention.
LC PUFAs are categorized according to the number and position of double bonds in the fatty acids according to a well understood nomenclature. There are two common series or families of LC PUFAs, depending on the position of the double bond closest to the methyl end of the fatty acid: the ω-3 (or n-3 or omega-3) series contains a double bond at the third carbon, while the ω-6 (or n-6 or omega-6) series has no double bond until the sixth carbon. Thus, docosahexaenoic acid (“DHA”) has a chain length of 22 carbons with 6 double bonds beginning with the third carbon from the methyl end and is designated “22:6 n-3”. Other important omega-3 LC PUFAs include eicosapentaenoic acid (“EPA”) which is designated “20:5 n-3” and docosapentaenoic acid (“DPA”) which is designated “22:5 n-3.”. In addition, omega-6 LC PUFAs can be used in connection with the present invention. For example, arachidonic acid (“ARA”) which is designated “20:5 n-6” and docosapentaenoic acid (“DPA”) which is designated “22:5 n-6” are suitable.
De novo or “new” synthesis of the omega-3 fatty acid DHA does not occur in the human body; however, the body can convert shorter chain fatty acids to LC PUFAs such as DHA, although at very low efficiency. Omega-3 fatty acids must be part of the nutritional intake since the human body cannot insert double bonds closer to the omega end than the seventh carbon atom counting from that end of the molecule. Thus, all metabolic conversions occur without altering the omega end of the molecule that contains the omega-3 double bond.
Over the past few decades, health experts have recommended diets lower in saturated fats and higher in polyunsaturated fats. While this advice has been followed by a number of consumers, the incidence of heart disease, cancer, diabetes and many other debilitating diseases has continued to increase steadily. Scientists agree that the type and source of polyunsaturated fats is as critical as the total quantity of fats. The most common polyunsaturated fats are derived from vegetable matter and are lacking in long chain fatty acids having 20 or more carbons (most particularly omega-3 LC-PUFAs). In addition, the hydrogenation of polyunsaturated fats to create synthetic fats has contributed to the rise of certain health disorders and exacerbated the deficiency in some essential fatty acids. Indeed, many medical conditions have been identified as benefiting from an omega-3 supplementation. These include acne, allergies, Alzheimer's, arthritis, atherosclerosis, breast cysts, cancer, cystic fibrosis, diabetes, eczema, hypertension, hyperactivity, intestinal disorders, kidney dysfunction, leukemia, and multiple sclerosis. Of note, the World Health Organization has recommended that infant formulas be enriched with omega-3 fatty acids.
The polyunsaturates derived from meat contain significant amounts of omega-6 but little or no omega-3. While omega-6 and omega-3 fatty acids are both necessary for good health, they are preferably consumed in a balance of about 4:1. Today's Western diet has created a serious imbalance with current consumption on average of 20 times more omega-6 than omega-3. Concerned consumers have begun to look for health food supplements to restore the equilibrium. Principal sources of omega-3 are flaxseed oil and fish oils. The past decade has seen rapid growth in the production of flaxseed and fish oils. Both types of oil are considered good dietary sources of omega-3 polyunsaturated fats. Flaxseed oil contains no EPA, DHA, or DPA but rather contains linolenic acid--a building block that can be elongated by the body to build longer chain PUFAs. There is evidence, however, that the rate of metabolic conversion can be slow and unsteady, particularly among those with impaired health. Fish oils vary considerably in the type and level of fatty acid composition depending on the particular species and their diets. For example, fish raised by aquaculture tend to have a lower level of omega-3 fatty acids than fish from the wild. In light of the health benefits of omega-3 LC PUFAs, it would be desirable to supplement foods with such fatty acids.
Due to the scarcity of sources of omega-3 LC PUFAs, typical home-prepared and convenience foods are low in both omega-3 PUFAs and omega-3 LC PUFAs (carbon chain length greater than 18, and preferably greater than 20), such as docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid. In light of the health benefits of such omega-3 LC PUFAs, it would be desirable to supplement foods with such fatty acids.
In light of the desirability of supplementing foods with omega-3 LC PUFAs and in view of the shortcomings of the prior art in providing these foods, there is a need for methods for enriching foods with omega-3 LC PUFAs and also for food oil compositions and food products comprising omega-3 LC PUFAs These and other needs are answered by the present invention.